Monday, January 25, 2016: 8:00 AM-9:30 AM
Cutting-Edge Technologies
Chair:
Omar Abdelaziz, Ph.D., Oak Ridge National Laboratory
Technical Committee: 01.03 Heat Transfer and Fluid Flow
CoSponsor: 08.04 Air-to-Refrigerant Heat Transfer Equipment
Recent innovations in heat and mass transfer equipment result in continued improvement in the tradeoff between pumping power and heat transfer augmentation. However, such designs require advanced manufacturing techniques, such as additive manufacturing. The major limiting factors of the additive manufacturing are the low thermal conductivity of the metal used, feature size resolution of 150 micron or more, and build time. In this seminar, internationally renowned experts present their activities through CFD modeling, shape optimization, additive manufacturing of surfaces with disruptively high airside heat transfer coefficients with low pumping power penalties, and additively manufactured heat pipes.
1 Numerical Study on Air-Side Performance for Round, Oval and Flat Tube Heat Exchangers with a Different Configuration of Fins
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Man-Hoe Kim, Ph.D., Kyungpook National University |
This seminar presents numerical investigation of air-side heat transfer and pressure drop characteristics for several different fin-tube type heat exchangers. Three different types of tube geometry and four different fins are considered. The CFD analysis is conducted by using commercially available software (ANSYS Fluent 6.3) for Reynolds number range of 35 -200, with the corresponding face velocity range of 0.3-2.0 m/s. After verifications of CFD results using available experimental data, a series of parametric study for design parameters of fin geometry has been conducted. The CFD results are reported in terms of Colburn j- and Fanning friction f-factors.
2 Tube Shape Optimization for Air-to-Refrigerant Heat Exchangers
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Vikrant Aute, Ph.D., University of Maryland |
It is well known that in heat exchangers for HVAC&R applications, the air-side is the dominant resistance. Significant effort has been devoted to improving the heat transfer performance of air-side surfaces. Conventional heat exchangers use round tubes or flat tubes but other shapes are seldom explored. In this seminar, an approach for shape optimization is presented that allows for full topology optimization of the heat exchanger tube for a given application. A prototype is fabricated using 3D Metal Printing technique and its performance is measured in the laboratory. The comparison of predicted vs. measured performance is presented and conclusions drawn.
3 Impact of Additive Manufacturing on Next Generation Thermal Management Systems
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Michael M. Ohadi, Ph.D., University of Maryland |
Increased pumping power penalty and manufacturing costs are among the major limiting factors for further enhancement of heat transfer coefficients for single phase and phase change processes. To develop next generation heat/mass exchangers that have better overall performance and can meet size, weight, and pumping power constraints while being cost affordable, one needs to utilize innovative designs, materials and manufacturing techniques. In this presentation we will review progress achieved in Phase I of a government-sponsored project in which a team of collaborators from academia, industry and sponsoring government agency achieved new levels of heat transfer performance on the air side.
4 Additively Manufactured Heat Pipes
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Patrick Geoghegan, Ph.D., Oak Ridge National Laboratory |
The majority of metal 3D printing machines use low thermal conductivity raw materials such as titanium alloys, cobalt chrome alloys and steel alloys. Thus any parts built will have limited heat transfer capabilities unless action is taken to deliberately enhance this characteristic. One such action is to embed heat pipes into the part as it is being built. This talk introduces a number of additively manufactured heat pipes designs and compares their performance to off-the-shelf units.